Conventional multi-component materials comprise a polymeric matrix that may contain filler materials used to contribute volume and/or desirable physical and/or chemical characteristics to the resulting finally-cured product. Such multi-component materials are used for many purposes, including coatings for an object or surface, to treat or protect the underlying object or surface, and/or to impart desired appearance, texture or other properties to the underlying object or surface. Polymeric matrix materials used in such conventional multi-component materials can comprise a variety of polymers, including polyurethanes and polyureas.
Such multi-component materials are known to include fillers that do not adhere well to the polymeric material matrix, e.g., when the matrix is a polyurethane or polyurea matrix. Also, many fillers can decrease desired properties like elasticity, fatigue resistance, and impact strength in the finally-cured product that can make the finally-cured product poorly suited to a number of desired end-use applications. Further, some fillers can also be relatively expensive, thereby increasing costs. Still further, some fillers may be toxic or harmful the environment when manufacturing the filler or disposing of the filler, thereby presenting undesired safety, health, and/or environmental issues.
Conventional systems for processing, handling, mixing and applying the components of a multi-component material are designed to handle low viscosity resins and hardeners, with low level of solid fillers incorporated in the resin. Fillers that contain larger particulate components, or mixtures of fillers having very different mixing properties, are generally incompatible with these conventional systems.
Additionally, conventional systems used for making multi-component materials meter the reactive precursor components using multiple independent pumps, wherein each pump has its own individual controllers and flow sensors to properly combine and mix the polymer matrix components. The added complexity is costly and makes the equipment less reliable in terms of variations in metering (less precision) as well as equipment failure. In addition, it is desired to have a precise and reliable metering system to meter the components of the multi-component material before mixing, so that, during mixing, specific, predetermined proportions of the components (the mix ratios) are closely maintained.
While such systems may be engineered to enable adjusting the mix ratio of precursor materials for dispensement to meet a particular end-use application, e.g., for a particular dispensement or delivery event, such systems are not capable of enabling one to adjust the mix ratio of precursor reactive components “on the fly” or during a particular dispensement or delivery event. Adjusting the mix ratio of the precursor reactive components during the actual process of dispensing or delivery is highly desirable for particular end-use applications. An example of such an end-use application includes almost all industrial floor coatings, were there is a need to create high abrasion resistance, hardness (e.g., for heavy equipment such as forklifts and the like), while at the same time the coating over the expansion joints needs to have high elongation (because of the continuous movement of the joints).
Additionally, conventional multi-component materials are somewhat limited in the combinations of physical properties that can be provided, which limitation is due to the slight variation in isocyanate mix ratio that is maintained for the purpose of providing a fully-cured product. Such conventional multi-component materials are known to have a variation in isocyanate mix ratio of about +/−5%. For certain end-use applications, it would be desirable to be able to provide a multi-component material having a greater variation of isocyanate mix ratio, while still maintaining the ability to provide a fully-curable product, for the purpose of providing an end product having a greater diversity and/or different combinations of physical characteristics, such as hardness, tensile strength, and elongation.
Such conventional systems typically use piston pumps for solid filled liquid resin material. However, piston pumps can provide non-uniform flow (i.e. a variation from a nominal, set, flow rate) due to the piston pump changing direction at the end of each stroke. Non-uniformity can produce mixing ratio variations that produce a non-uniform multi-component product, where polymerization is incomplete, and is particularly problematic for some filled materials because it can produce localized regions of inferior product. For example, when applied as a relatively thin layer (e.g., less than about 1 cm in thickness, or less than about 5 mm in thickness), localized regions of high or low filler concentration can produce spots where the solidified material is weakened by having too much filler, or excessively stiff or brittle where too little filler is present. Maintaining a relatively homogeneous distribution of filler is thus especially important for embodiments described herein where the material is used to form a thin layer on a surface.
Some known multi-component materials comprise compositions of resin, curing agent, and finely divided particulate filler that are suitable for spray application. Application by spraying further complicates selection of filler materials and preparation of the resin and/or curing agent component. The reactive component containing a filler must be prepared as a suspension for spraying, and the filler must be sized suitably for spray application. The filler must be kept in a homogeneous suspension in one of the reactive components, typically the resin, while feeding it into a spraying device and mixing it in proper mix ratio with the other component (usually the curing agent), in preparation for spraying. It must then be formed into an aerosol with droplet size suitable for spraying onto a surface to be coated before polymerization occurs to an extent that interferes with spraying onto a surface. While spray-on materials such as polyurethane and polyurea materials that polymerize rapidly upon application are well known in the art, such materials having particulate fillers as described herein have not been available due to the complexity of forming a suitable homogeneous mixture for aerosol application to produce a uniform product.
It is, therefore, desirable that multi-component materials be developed comprising a filler material that introduces desired properties into the finally-cured product, and does so in a manner that does not detract from such properties as elasticity, fatigue resistance, and impact strength, that does not introduced unwanted safety, health or environmental issues, and that does not detrimentally increase product costs, or that decrease product costs. Additionally, it is desired that a system/apparatus be developed that is capable of mixing greater levels of and diverse types of fillers (including large particle fillers), and incorporating the filler into the precursor materials to provide a delivery product having the filler uniformly dispersed within the polymer matrix.
It is further desired that such system/apparatus be engineered to enable combining the precursor materials at precise mixing amounts and at different and greater variations of mix ratios while such combined precursor materials are being dispensed to provide fully-cured products well suited for end-use applications, thereby providing “on the fly” adjustability of the precursor mix ratio. It is still further desired that such system/apparatus be engineered in a manner that produces a uniform flow of precursor reactive materials, thereby producing a dispensed product having a uniform distribution of the multi-component material.
Finally, it is desired that the system/apparatus be engineered in a manner that produces a homogeneous mixture of reactive precursor components and particulate fillers suitable for aerosol application to produce a uniform product. Such compositions, systems/apparatus and methods will allow for the preparation of highly filled, viscous reactive components (resins and/or curing agents) for making filled multi-component materials, with precise metering to produce a consistent and homogeneous sprayed-on product, at variable mix ratios “on the fly” in a reliable manner, without the need for complex mechanisms.